This proposal is a collaborative, multi-disciplinary program involving researchers at the College of Engineering and School of Medicine at the University of Washington, and the School of Engineering at the Pennsylvania State University. Our objective is to develop ultrasonic micromotors and novel endoscopic imaging devices ;apable of beam scanning and focus tracking using the ultrasonic micromotors. The endoscopic imaging device ;an integrate optical coherence tomography (OCT) with confocal microscopy, enabling high resolution imaging of internal organs at the cellular level. Many cancers arise from epithelial layers and are characterized by changes in tissue and cellular structure prior to metastasis. Development of a technology that enables imaging of tissues internal to the body at cellular level could permit cancer detection at early stages. OCT is an emerging medical diagnostic technique capable of imaging tissue microstructures in vivo and in real time. Conventional OCT is essentially a low numerical aperture (N.A.) confocal microscope with the axial resolution enhanced by using coherence gating. OCT imaging resolution can be improved when high N.A. beam-focusing optics are employed. High-resolution imaging of internal organs with high N.A. OCT/confocal microscopy requires novel miniature scanners that can be delivered endoscopically to the internal organs to scan the beam and track the focus. The hypothesis of this proposal is that novel ultrasonic micromotors that can be integrated within a catheter/endoscope enable beam scanning as well as focus tracking, thus permitting cellular level imaging. The specific aims of this exploratory proposal are: 1) to develop ultrasonic micromotors and explore the feasibility of using the micromotor as a scanner for OCT imaging catheters/endoscopes; 2) to explore a focus tracking mechanism using the micromotor and to develop a spiral beam scanning scheme to increase imaging coverage; 3) to develop a prototype micromotor-based imaging catheter/endoscope with a focus tracking capability and explore the unification of OCT and confocal microscopy within the scanning catheter/endoscope; to characterize the catheter/endoscope performance and demonstrate high-resolution imaging using tissue phantoms and in vitro biological tissues; 4) to investigate the feasibility of the prototype catheter/endoscope for in vivo cellular-level imaging of the esophagus in an animal model. If successful, this technology could enable detection of premalignant conditions (such as dysplasia) or early cancers.